Boron Neutron Capture Therapy in Treating Patients With Melanoma

DISEASE CHARACTERISTICS: * Histologically confirmed melanoma * Evaluable disease * Lesion(s) to be irradiated must be located in 1 of the following areas: * On an extremity * On the head or neck (including the scalp) * In the subdermal lymphatics (excluding the proximal axilla) * Area to be irradiated must not exceed a maximum dimension of 10 cm * Maximum tumor depth from the surface of the skin cannot exceed 6 cm PATIENT CHARACTERISTICS: Age * 18 and over Performance status * ECOG 0-1 Life expectancy * More than 6 months Hematopoietic * Not specified Hepatic * Not specified Renal * Creatinine normal Cardiovascular * No history of severe cardiac disease * No uncontrolled arrhythmias or conduction defects * No unstable or newly diagnosed angina pectoris * No recent coronary artery disease * No congestive heart failure Other * Not pregnant * Negative pregnancy test * No history of phenylketonuria * Must have sufficient mental competence PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * Not specified Endocrine therapy * Not specified Radiotherapy * No prior radiotherapy to study sites Surgery * Not specified